I'm struggling with the top left of the grid.
1a Dangerous substance pupils detected - initially hidden in a carpet (5,1,4) ????S/?/??U? Is it anything to do with Cleopatra?
14a Blue tin contains tip of eraser and another stationery item (8) C????L???
4d Exhausted old man takes drug at club (8) ??A?B???
Many thanks folks. I didn't know the word CERULEAN, but my dictionary says it means deep blue The clue is hard to parse, presumably tin=CAN containing E and RULE. Inelegant, I would say.